International patent publication WO2011/018113 discloses a hybrid circuit breaker with a mechanical switch 31 and a semiconductor breaker device 32 parallel to the mechanical switch 31. An embodiment is disclosed wherein the semiconductor device 32 comprises a bridge rectifier 37 and an IGBT 36.
French patent publication FR-A-2952470 discloses a circuit breaker for alternating current applications, using a control unit for controlling an interrupter having a mechanical switch, varistor and semiconductor switch in parallel.
International patent publication WO2011/116832 discloses a hybrid circuit breaker for interrupting a fault current in an electrical circuit line. A mechanical breaker is connected in parallel to a semiconductor device, which takes overcurrent temporarily when the mechanical breaker is opened. In the embodiments disclosed, the semiconductor device is a set of serial or parallel connected controllable semiconductor units, such as thyristors, GTO's, IGBT's or IGCT's.
European patent publication EP-A-2469554 discloses a hybrid switching circuit, comprising a power semiconductor parallel to the switch poles of a controlled electromagnetic relay, it is described that the semiconductor is turning off at a zero crossing of the load current. This makes short circuit switching impossible because the energy must be carried until the zero crossing. In the time period between occurrence of the short circuit and the actual breaking of the circuit, the current and the energy will be much too high to withstand by a semiconductor.
International patent publication WO2011/057675 A1 discloses a high voltage circuit breaker (>10 kV) especially for DC applications, wherein a main breaker, non-linear resistor and a high speed switch are connected in parallel. The main breaker comprises one or more semiconductor switches of a first current direction.